This invention relates to a method of measuring a gas flow. More particularly, but not by way of limitation, this invention relates to a method of measuring a dry gas flow from hydrocarbon wells.
According to the National Energy Board (NEB), Canada has about 53 trillion cubic feet (Tcf) of marketable gas supply. The Western Canada Sedimentary basin (WCSB) accounts for more than half. In addition, the magnitude of unconventional gas resources in place is estimated to be quite formidable. However, development of this natural resources require substantial capital expenditures and extensive drilling due mostly to the decline of the know reserve pool sizes and continued high demand for natural gas.
Even though the economic climate seems favourable, producers continue to face the predicament of developing these marginal pools within budgets and strict regulatory regime. According to the data found within the Alberta Energy and Utilities Board (EUB) publication titled: ST98-2006, production from the WCSB is not up to expectations, especially from unconventional sources.
Many producers have started to explore emerging operational paradigms and are open to adapting new technology devices. However, due to the realities of the labour markets, and the nature of these new technologies, typical well costs are still considered relative high in relation to the rate of returns of investment. These costs can range between 2 million to 2 hundred thousand depending on location and existing infrastructure.
Flow metering costs as a proportion of total revenue becomes significant as drill densities increase and the size of gas pools being developed get smaller. Yet, regulators continue to enforce strict measurement guidelines, effective well and reservoir management is dependent on accurate well flow data in order to design the production and processing infrastructure, control of hydrates, and the determination of optimal flow rates. Finally, accurate flow metering becomes a requirement to insure fair allocation of total production volumes when more than one party is using common pipelines, and processing facilities in joint venture relationship. One of the potential solutions for this economical dilemma which can be offered to producers is wet measurement of the flow stream, stated otherwise, metering of natural gas without separation of the liquids from the production stream.
Most typical gas wells with free liquid (water, condensate, and or a combination) in the flow stream, often require a gas-liquid separator to be installed upstream of the gas measurement device to maintain measurement accuracy within the prescribed limit established by the EUB and other similar government regulatory bodies.